The present invention relates to an electronic accounting machine of variable configuration comprising a device for automatically initializing the machine on the basis of the number and type of peripherals connected thereto.
As is known, accounting machines may have a plurality of configurations according to the kind of application for which they are intended. More particularly, each configuration depends on the number of peripheral units connected to the basic machine, such as magnetic tape readers, paper tape punch/readers, etc. For each configuration it is necessary to define a reserved zone of the memory at the disposal of the supervisory program and not accessible to the user program for recording the information which concerns the exchange of data with the connected peripheral units.
The problem for medium-large computers is solved by using one or more computers of lesser power (channel controller) for handling the conversation with the peripheral units.
Some electronic accounting machines of medium power, on the other hand, define a memory zone capable of handling the maximum number of peripheral units which can be connected and, in the case of a smaller number of peripherals, much of this zone remains unutilized. Since this unutilized zone occupies only a very small fraction of the capacity of the memory available to the programer, the problem of optimizing the dimensions of the reserved memory zone does not exist.
In the case of small-sized accounting machines there is the problem of optimizing the dimensions of the reserved zone as a function of the number and type of peripheral units connected. In fact, for such machines it is a very frequent occurrence to vary the configuration of the peripheral units as a function of the scope of the services required. Therefore, a machine may be extended at the premises of the user by adding or substituting peripherals. If there were always a reserved zone sufficiently large for the maximum configuration, a conflict exists between, on the one hand, defining a reserved zone capable of handling the maximum number of peripherals and of, on the other hand, providing a memory of a sensible size for connecting the minimum number of peripherals required by the particular application.
In this case, since the memory available to the user is the difference between the capacity of the memory and the reserved zone, the former would be insufficient to contain the programs required even for the minimum configurations. Therefore, the capacity of the memory must be extended and the memory would not be fully utilized.
The object of this invention is therefore to overcome such problems.